--- On Thu, 3/12/09, Georg Pfundstein wrote:
> I am running a truncated regression with cubic splines,
> which works quite well i think. <snip> i also want to
> calculate and plot confidence bounds for the regression
> splines.
*------------------ begin example ----------------
sysuse auto, clear
mkspline cubsp_mpg1 18 cubsp_mpg2 = mpg, marginal
foreach var of varlist cubsp* {
qui replace `var' = `var'^3
}
gen cubsp_sq = mpg^2
gen cubsp_lin = mpg
reg price cubsp* foreign weight
preserve
sum weight if e(sample)
replace weight = r(mean)
replace foreign = 0
predictnl yhat = xb(), ci(lb ub)
twoway rarea lb ub mpg, sort || ///
line yhat mpg, sort ///
legend(off) ///
title("predicted price for US cars with average weight")
restore
*-------------------- end example ---------------------
You might also be interested in this talk held at the
last German Stata Users' Group meeting:
http://ideas.repec.org/p/boc/dsug09/04.html
And this talk held at the last Swedish Stata Users'
Group meeting:
http://www.stata.com/meeting/sweden09/se09_orsini.pdf
Hope this helps,
Maarten
--------------------------
Maarten L. Buis
Institut fuer Soziologie
Universitaet Tuebingen
Wilhelmstrasse 36
72074 Tuebingen
Germany
http://www.maartenbuis.nl
--------------------------
*
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